Film controlled automatic safety shutter for moving picture projectors



June 20, 1950 MANNON 2,512,030

FILM CONTROLLED AUTOMATIC SAFETY SHUTTER FOR MOVING PICTURE PROJECTORSFiled Feb. 25, 1946 2 Sheets-Sheet l INVENTOR. L1. oya MAM/02v. BY

7 .I w M A 7 TOR/V1.5 Y5,

June 20, 1950 2,512,030

L. MANNON FILM CONTROLLED AUTOMATIC SAFETY SHUTTER FOR MOVING PICTUREPROJECTORS Filed Feb. 25, 1946 2 SheetsSheet 2 INVENTOR.

LL 0Y0 jVA/y/w/v. BY

ATTOR/VEXF.

Patented June 20, 1950 FILM CONTROLLED AUTOMATIC SAFETY SHUTTER FORMOVING PICTURE PRO- J ECTORS Lloyd Mannon, San Francisco, Calif.

H Application February 25, 1946, Serial N 0. 650,008

6 Claims. 1

An object of my invention is to provide a film controlled automaticsafety shutter for a moving picture projector that will prevent the filmfrom catching fire should it break or pass too slowly through the pathof light.

A further object of my invention is to provide a device of the typedescribed in which the safety shutter is opened, held in open position,and closed by the mechanical force created by the moving film passingthrough the projector. The safety shutter operates independently of themechanism in the projector and is dependent on the safe passage of thefilm through the projector. The shutter will open only when the film ismoving through the projector at a predetermined speed and in a safemanner.

The invention may be used for other purposes than to control a movingpicture projector fire shutter, such as for example the operation of aswitch in the motor circuit that drives the projector. The invention canalso be used in a motion picture camera to open the lens aperture whenthe film is moving at the proper speed and to close the lens aperturewhen the film movement drops below this speed. The invention may operatea switch in the motor circuit rather than open the lens aperture ifdesired.

Other objects and advantages will appear in the following specification,and the novel features of the device will be particularly pointed out inthe appended claims.

My invention is illustrated in the accompanying drawings forming a partof this'application, in which: V

Figure 1 is a perspective view of a moving picture projector showing mydevice operatively applied thereto;

Figure 2 is a longitudinal section through the governor, portions beingshown in elevation;

Figure 3 is a perspective view of the clutch used with the governor;

Figure 4 is a perspective view of the flyweights and associate mechanismforming a part of the governor;

Figure 5 is a horizontal section of a modified form of governor control,and is taken along the line V-V of Figure 6;

Figure 6 is a front elevation of Figure 5 with the front casing wallbroken away to show the shutter actuating parts; and

Figure 7 is a transverse section through the governor used with themodified form illustrated in Figures 5 and 6.

While I have shown only the preferred forms of my invention, it shouldbe understood that 2 various changes or modifications may be made withinthe scope of the appended claims without tdeparting from the spirit andscope of the inven- In carrying out my invention, I make use of a movingpicture propector as indicated generally at A in Figure 1. The projectorhas a film feeding magazine B and a film take-up magazine C. A film D isfed from the upper magazine B, around an upper feed sprocket l, and thefilm is then passed in front of a shutter mechanism indicated generallyat E, and past an intermittent sprocket 2. The film then passes to thespool and governor indicated at F which is my invention and then aroundan idler to a hold-back sprocket 3. From the sprocket 3, the film moveson into the sound reproducing head G and then into the lower magazine C.Electrodes El are shown in Figure 1 for producing an are light E2. Theparts thus far described with the exception of the combination spool andgovernor F, form no part of my invention except insofar as theycooperate with the parts now to be described.

I will now describe the construction of the combined film spool andgovernor F. In Figure 2, the film spool is shown at 4 and it isrotatably mounted on a hollow shaft 5. The shaft in turn is rigidlymounted in a support 6. The spool is held against longitudinal movementto the left in Figure 2 by a disc I that is secured to the shaft 5 by aset screw 8. The spool 4 has an extension at one end that has a recess 9for receiving a part of the governor mechanism.

A base In with a cylindrical bore H is slipped over the shaft 5 and issecured to the spool 4 by set screws l2. Figures 2 and 4 illustrate howthe base [0 pivotally carries two pairs of bell crank levers i3 and M.The pairs of levers are pivoted at 15 to parallel fiat faces I6 on thebase and carry flyweights l1. Coil springs 18 yieldingly urge theweights toward each other.

Figures 2 and 3 show a friction disc [9 sliding on the hollow shaft 5and carrying longitudinally extending fingers 20. The bell crank leversl 3 and [4 have forked ends engaging with pins 2| that are carried bythe fingers. When the weights fly apart due to centrifugal force, thefriction disc will be forced against the friction face 22 of a casing23. A torsional spring 24 is mounted in the casing and has one endsecured to the shaft 5. The casing is secured to a shaft 25 that isrotatably mounted in the hollow shaft 5. The end of the compartment orrecess 9 is closed by a cover plate 26 and a set screw 21, carried-bythe plate 26 bears against the end of the shaft 25.

The shaft 25 carries a worm 28 that meshes with a worm gear 2% Referringto Figure 1, it will be seen that the worm gear 29 is mounted on a shaft39 and that the shaft is rotatably mounted in the casing wall St. Apinion 32 is mounted on the shaft and meshes with a quadrant 33. Thequadrant is pivoted at 34 and carries a fire shutter that is designed tocover a light opening 36. When the film is moving at the proper speed,the weights ll overcome the springs l8 and fiy out, causing the bellcranks l3 and I l to force the friction clutch it against This willrotate the casing 23 until permitting the clutch plate l9 to slip overthe clutch face 22. The rotation of the casing however, is sufficient torotate the shaft through a desired number of revolutions for causing theworm 23, worm gear 2% pinion E32 and. quadrant 38 to swing the fireshutter for uncovering the opening 353. As soon as the film speeddecreases below a predetermined point, or should the film break, theweights I? will loose centrifugal force, and the pressure holding theclutch it against the face 22 will be removed and the spring'Zd willinstantly return the casing 23 to its starting position. and will causethe fire shutter to immediately cover the opening 1 and prevent the heatfrom the light rays from fire to the film.

. In Figures 5, 6 7, I show a form of the invention for accomplishingthe same purpose. A film spool. 3? takes the place of the spool 3 andthe spool is mounted on a shaft that is rotatably mounted in a support Aworm lt is mounted on the shaft 38 and rotates worm gear ll. The support39 rotatably carries a shaft.

Bell-crank levers it are actuated by the out wardly moving weights andlift a collar ll that. is slidably mounted on the shaft A bell-cranklever 58 is pivoted at ii; to a bracket til and has one end acted upon bthe movement of the collar 41 along its supporting shaft. The other endof the bell-crank lever 48 has a, lever connected thereto by a pin 337).The lever 18a is pivoted at 80 and has a link 5i connected thereto, theopposite end of the link being pivotally connected at 52 to an 5:2.Figures 5 and 6 show the arm pivotally mounted at 5 3 to the casing wall3| that has the opening therein.

The opening 3b is provided with horizontally disposed guide channels 55in which a fire shutter 5% is slidably mounted. The arm 53 has a forkedend that receives a pin 57 that slides in a slot 58 provided in thecasing wall 3!. The pin is carried by a projection that depends from thefire shutter 555. When the film D passes over the spool 3'! at asufiicient speed, the governor 63 will cause the collar to move the bellcrank lever 8 to open the fire shutter 55. Any failure upon the part Ofthe film to maintain the pr er speed for safety or should the filmbreak, the spool 31 will slow down in its rotation or will stop and ineither event the springs 59 will force the weights back and thebell-cranks 56 will cause the collar ll to immediately move the fireshutter and close the opening 36. This will prevent the heat from thecarbon light setting fire to the film.

Although I have shown the shutter 56 disposed on the outer surface ofthe casing wall 3|, it is obvious that it can be mounted on the insideof the casing. The same is true of the fire shutter 35. This shutter maybemounted within the casing and thus protect-the pinion 3| and thequadrant 33. The springs 59 are used to overcome the centrifugal forceof the weights t5 and determine the speed of the film at which the fireshutter operates. A switch, not shown, may be operated when the fireshutter is closed, to open the motor circuit.

1.. In combination, a rotatable member, a hollow shaft for rotatablysupporting the member,said member having a cavity therein, a combinedgovernor and clutch mounted in the cavity and including weights,bell-crank levers pivotally supporting the weights, spring means forurging the weights toward each other, a torsional spring housingrotatabl about the same axis as. the hollow shaft and constituting oneelement of a clutch, a clutch plate rotatable with the member andmovable by the levers against the clutch face of the housing when theweights fiy outwardly due to centrifugal force generated by the rotationof the member, whereby th housing will be rotated, a torsional springmounted'in the housing and having one end secured thereto and the otherend secured to the hollow shaft, and a second shaft mounted in th hollowshaft-and beingrotated by the housing during the'winding of thetorsional spring, said second shaft ceasing to rotate when the forceexerted by the torsional spring balances the force of the clutch plateagainst the housing.

2. In combination, a rotatable member, a hollow shaft for rotatablysupporting the member, said member having a cavity therein, a combinedgovernor and clutch mounted in the cavity and including weights,bell-cranklevers pivotally supporting the weights, spring means forurging the weights toward each other, a torsional. spring housingrotatable about the same axis as the. hollow shaft and constituting oneelement 1 of a clutch, a clutch plate rotatable with the member andmovable by the levers against the clutchiface of the housing when theweights fiy outwardly due to centrifugal forc generated by the rotationof the member, whereby the housing will be rotated, a torsional springmounted in the housing and having one end secured-thereto and'the otherend secured to the hollow shaft and a sec-0nd shaft mounted in thehollow shaft and being rotated by the housing during th -winding of thetorsional spring, said second'shaft ceasing to rotate when the forceexerted'byithe torsional spring balances the force of the clutch plateagainst the housing, a shutter normally closing an opening, and meansactuated by the second shaft when rotated by the housing during thewinding :up of the torsional spring forremoving the shutter from theopening, said last-named means again moving the shutter over theopem'ngwhen the rotatable member stops or slows down below a predeterminedspeed.

3. In combination, arotatable member, a hollow shaft for rotatablysupporting'the member, a combined governor'andclutch and includingweights and two clutch plates; spring means forurging the weights towardeach other; on of the clutch plates-being rotatable with the -member andmoveable by the governor against the other clutch plate when the weightsfly outwardly due to centrifugal force generated by th rotation of themember, whereby the said other clutch plate will be rotated, a torsionalspring having one end secured to the said other clutch plate and theother end secured to the hollow shaft, and a second shaft mounted in thehollow shaft and rotated by the said other clutch plate during thewinding of the torsional spring, the second shaft ceasing to rotate whenthe force exerted by the torsional spring balances the force of theclutch plate connected to the governor.

4. In combination, a rotatable member, a hollow shaft for rotatablysupporting the member, a combined governor and clutch and includingweights and two clutch plates, spring mean for urging the weights towardeach other, one of the clutch plates being rotatable with the member andmoveable by the governor against the other clutch plate when the weightsfly outwardly due to centrifugal force generated by the rotation of thmember, whereby the said other clutch plate will be rotated, a torsionalspring having one end secured to the said other clutch plate and theother end secured to the hollow shaft, and a second shaft mounted in thehollow shaft and rotated by the said other clutch plate during thewinding of the torsional spring, the second shaft ceasing to rotate whenthe force exerted by the torsional spring balances the force of thclutch plate connected to the governor, a shutter normally closing anopening, and means actuated by the rotation of the second shaft duringthe winding up of the torsional spring for removing the shutter from theopening, said last-named means again moving the shutter over the openingwhen the rotatable member stops or slows down below a predeterminedspeed.

5. In combination, a rotatable member, a shaft for rotatably supportingthe member, a combined governor and clutch and including weights and twoclutch plates, spring means for urging the weights toward each other,one of the clutch plates being rotatable with the member and moveable bythe governor against the other clutch plate when the weights flyoutwardly du to centrifugal force generated by th rotation of themember, whereby the said other clutch plate will be rotated, a secondspring means for yieldingly holding the said other clutch plate in :apredetermined position with respect to said rotatable member, and asecond shaft rotated by the said other clutch plate during the storingof energy in the second spring means, the second shaft ceasing to rotatewhen the force exerted by the stored up energy in the second springmeans balances the force Of the clutch plate connected to the governor.

6. In combination, a rotatable member, a shaft for rotatably supportingthe member, a combined governor and clutch and including weights and twoclutch plates, spring means for urging the weights toward each other,one of the clutch plates being rotatable with the member and moveable bythe governor against the other clutch plate when the weights flyoutwardly due to centrifugal force generated by the rotation of themember, whereby the said other clutch plate will be rotated, a secondspring means for yieldingly holding the said other clutch plate in apredetermined position with respect to said rotatable member, a secondshaft rotated by the said other clutch plate during the storing ofenergy in the second spring means, the second shaft ceasing to rotatewhen the force exerted by the stored up energy in the second springmeans balances the forc of the clutch plate connected to the governor, ashutter normally closing an opening, and means actuated by the rotationof the second shaft during the storing of energy in the second springmeans for removing the shutter from the opening, said last-named meansmoving the shutter over th opening when th rotatable member stops orslows down below a predetermined speed.

LLOYD MANNON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,022,320 Kershaw Apr. 2, 19121,417,595 Daniels Ma 30, 1922 1,537,830 Kiral May 12, 1925 1,628,258Malm May 10, 1927 2,009,532 Taylor July 30, 1935 2,280,825 Holman Apr.28, 1942 FOREIGN PATENTS Number Country Date 455,280 France May 20, 1913381,241 Germany Sept. 18, 1923

